Coil unit



N. DINION COIL UNIT Feb. 2, 1937.

Filed Feb. 7, 1936 1 INVENTOR. BY M Z/ y 4 ATTORNEY;

Patented Feb. 2, 1937 UNITED STATES PATENT OFFICE COIL UNIT Application Feb. 7, 1936, Serial No. 62,791

1 Claim.

This invention relates to coil units adapted for various uses in the electrical art, and is herein illustrated as embodied in a field coil unit especially designed for use in connection with sound reproducers of the type generally known as loudspeakers.

The coil unit herein illustrated is characterized, at least in part, by the fact that one of the ends of the spool or spool-like structure on which the coil windings are carried is so formed as to provide a concave depression coaxially disposed with relation to the spool and the core opening provided therein.

Coil units of the character briefly described above are recognized as possessing certain inherent advantages, from a mechanical standpoint, but the cost of such units, due to manufacturing difficulties heretofore encountered, has been such as to render them commercially 2 prohibitive.

An important object of the present invention is to provide a coil unit, of the character above described, which is so improved and is structurally such that it may be manufactured at a cost sufficiently low to justify its commercial use in lieu of coil units of the type which it is intended to supersede.

Other objects and advantages of the invention will become apparent from the following description when taken in connection with the accompanying drawing, in which- Fig. 1 is a face view of a blank adapted to form the concave end of a spool embodying the present invention; Fig. 2 is a view similar to that of Fig. l and illustrating the blank of Fig. l as having been distorted to form a frustro-cone-shape element, the contour of which is maintained by securing adjacent ends of the blank in an abutting relation; Fig. 3 is a view in elevation of the 0 frustro-cone-shape element of Fig. 2 prior to distortion of its scored or slitted flange-forming margin into a plane perpendicular to its axis; Fig. 4 is a face View showing a retaining or reinforcing ring as having been applied to the distorted flange-forming margin of the frustrocone-shape element for retaining such margin in fiange-forming position; Fig. 5 is a view in elevation of the frustro-cone-shape element of Fig. i; Fig. 6 is a face view of a blank adapted to form the flat end of a spool-like structure embodying the present invention; Fig. 7 is a View showing the concave end of a spool embodying the present invention; Fig. 8 is a transverse sectional view 5 taken on line 88 of Fig. '7 and showing coil windings carried by the spool, and Fig. 9 is a perspective View showing a completed coil unit.

The completed coil unit illustrated in Fig. 9 includes, as shown most clearly in Fig. 8, a spool or spool-like structure l0 which is formed of a suitable insulating material, such as cardboard or the like, and is composed of three primary elements, namely, a tubular core member II and a pair of end members [2 and M, the former of which is substantially flat and the latter of which is shaped to present a concave depression l5 coaxially disposed with relation to the spool and the core opening provided therein.

The end member I2 of the spool-like structure I0 is produced from a disc-like blank I6 (Fig. 6), characterized by the fact that it is provided with a plurality of prong-like wings I! which are grouped about and normally project toward the center of the blank. The wings I! terminate in points located on an imaginary circle described about the center of the blank and are adapted to be folded back into right-angle positions with relation to the blank so as to then permit the blank as a spool-end-forming element to be slipped onto the tubular core member H. In order to facilitate folding back of the wings ll, the blank [6 is scored to define a circular line of fold l8 passing through the points of juncture between the several wings and the body portion of the blank, it being noted that the diameter of the opening, which is afforded when the wings assume right-angle positions with relation to the blank and which is substantially equal to the diameter of the tubular core member II, is such as to promote a snug fit of the core member within the spool-end-forming element.

The end member M of the spool-like structure It] is produced from an arcuate shaped blank 20 (Fig. 1), which is characterized by the fact that it is provided at its margin with a series of radial scorings 2| and an arcuate scoring 22, adjacent to the latter of which scorings the inner ends of the scorings 2| terminate. The blank 20; is adapted to be distorted to form the frustro-coneshape end member M, the contour of which is maintained by securing adjacent ends of the blank in an abutting relation by adhesively attaching a pair of strips 25 and 26, of suitable material such as paper, to opposite sides of the blank in an overlapping relation to the marginal areas adjacent the abutting edges. After applying the strips 25 and 26 to the end member I4, the marginal area of that member is folded back along the line of scoring 22 into flange-forming position as shown in Fig. 5, such folding back or distortion of the marginal area being readily permitted due to the presence of the radial scorings 2|, as will be appreciated when it is taken into account that the material of which the blank 20 is formed breaks down or separates along the scorings 2|, thus allowing the perimeter of the end member M to expand as its margin is folded back along the line of scoring 22 and is separated into a plurality of radially extending tabs 21. In order that the deformed marginal area of the end member l4 may be retained in a plane perpendicular to the axis of that element, a retaining or reinforcing ring 28, of suitable material such as paper, is adhesively attached to the outer face of the margin.

Inasmuch as the blank 20 is scored to define, on the end member I4, a circular line of fold 3| (corresponding to the line of fold I8 hereinbefore described) and is so formed as to afford a series of spur-like wings 32 (corresponding to the spurlike wings I! hereinbefore described) i, it becomes obvious that the end member is adapted to be placed on the tubular core member II in the manner described in connection with the end member l2.

When the end members l2 and M are assembled in the spool-like structure It), the spurlike wings I! are complementary to and fit within the spaces afforded between the wings 32, and likewise the wings 32 are complementary to and fit within the spaces afiorded intermediate the wings IT. The end members l2 and I4 may be adhesively held in a fixed relation on the tubular core member I I and may be further held with respect to each other by adhesively attaching a strip 34, of suitable material such as paper, to the outer surfaces of the inter-engaging spur-like wings I? and 32.

Pursuant to assembling the spool-like structure Ill, the wire necessary to form the coil windings 35 may be wound about the hub portion of that structure intermediate its end members [2 and M, whereupon the unit may be complemented by applying a suitable peripheral and marginal covering 36, through which may extend coil leads 31, to which the respective ends of the coil windings 35 are attached before the covering is applied.

Although the herein described structure is at present regarded as the preferred form of the invention and the herein described procedure as the preferred method of producing that structure, it will be understood that various changes, both as to structure and as to procedure, may be adopted without departing from the spirit of the invention or the scope of the following claim.

What is claimed is:

In a coil unit: a spool structure including a core member; and an end member attached to said core member and comprising an arcuate element presenting a frustro-cone-shape and having its opposite ends anchored with relation to each other; a flange carried at the perimeter of said element and disposed in a plane perpendicular to its axis, said flange including a plurality of tabs formed integral with said element; and a reinforcing element adhesively attached to said tabs for retaining them in said plane.

NATHAN DINION. 

